Tetraphobia is the practice of avoiding instances of the digit 4. It is a superstition most common in East Asian nations and is associated with death.
An elevator control panel in a residential apartment building in Shanghai with no floor numbered as the 4th
The number 4 missing in a parking lot in Japan
Phone numbers for sale in Hong Kong, containing a lot of fours.
4th floor labelled "F", 13th floor labelled as usual
A superstition is any belief or practice considered by non-practitioners to be irrational or supernatural, attributed to fate or magic, perceived supernatural influence, or fear of that which is unknown. It is commonly applied to beliefs and practices surrounding luck, amulets, astrology, fortune telling, spirits, and certain paranormal entities, particularly the belief that future events can be foretold by specific unrelated prior events.
Witch-hunting is commonly motivated by religious superstition